i was just wondering becasue when i had my ecu chipped they set the vtec at 4400 RPM, and its just a stock gsr motor. Now would this hinder my performance, or is it better?? By the way, my car seems to lag as soon as vtec kicks in all the way till redline. what do u guys think? please only peeps who know what they are talking about reply. And plese let me know what the stock vtec crossover is, because i have a vafc, and ill change it to stock, if u guys think it will help. thanx
manny

 

vtec crossover is 4400.

-rod

 

5500

 

well i just searched to see if it was right, and it is......vtec kicks in at 4400 and then the secondarys open at 5800. Now my question is i have a skunk2 intake manifold on my gsr, should i up the vtec to 5700 like the type r(since its a copy of the type r anyway). and i dont use the secondarys anymore. anyone else with a s2 im on a gsr??? i would like to know if u left it stock or what?? thanx
manny

 

I think u cant use the stock GSR ecu because it has dual butterfly program. You need to chip it or get another ecu that utilizes the single butterfly program. ie. P30 or P73

 

I'm pretty sure that's backwards. The vtec crossover is at 4400 and the secondaries open at 5800.

 

thats right. Its vtec then secondaries

 

I wouldnt raise the VTEC point to 5700 like the ITR if you have the stock GSR tranny. Just my .02

 

That isn't the reason for not changing you VTEC switch over point.

Vtec is based on your CAMS - therefore you need to set the VTEC point to where it makes the smoothest (and most power) transision from the primary to secondary lobes.

Therefore, if you are using GSR cams, there is no point in changing the VTEC switchover point simply because you have a different intake manifold or tranny. The cam profiles are still the same.

If you switched cams, then you need to reset the vtec switch over to the manufactures recommended point - or if you have access to a dyno, then where the 2 torque graphs cross (primary vs secondary).

 

i have a b16a ecu, but i guess when the guy chipped it he must have that that i had the stock intake manifold.. but now that i dont have the secondaries, i dont think that vtec need to kick in that early. and as for the cams, so i should switch to b16a cams (less aggressive than gsr) so i can switch my vtec at 5700?? i thought people did it the other way around...u put gsr cams in a b16a because they are a bit more agressive. but i will try out my friends b16a ecu and let you know how it pulls, because thats what i have a problem with.... it lags from vtec till redline. but thanx for your help guys i still would like to see peeps with the s2im in there gsr's.

 

Well first off, you are using the wrong ECU for you setup. The GSR ecu is more aggressive than the USDM B16 ecu.

Not to mention the vtec switch over is WAY to late on the B16 for use with your GSR cams.

You may "feel" that the b16 kick in a lot harder at vtec, (which it would) because you are riding on the primary lobes FAR beyond the point of where they make any power, so once vtec switches at 5700rpms on the B16 ecu, you will get a mad rush of power.

What does that mean? It means from 4400-5600rpms, you are LOSING power - which if it DID switch to the secondary lobes, you'd be making more power because the primary lobes simply don't make any more power beyond factory vtec point.

 

4400 and its freaking loud.

 

Is it really? I always thought the gsr was "quiet"...not that that's a bad thing.

-Rod

 

To The Top!

My vtec engauges at 4,700 RPM on the 98 GSR / Eg Hybrid
--stock obd1 P72 ECU

I'm not sure when the secondaries kick-in. I know it's up there. Just I never look down long enough to see when it engauges.

THe sound is FAWKIN' AWESOME though

 

in the gsr,honda made the vtec x-over at 4400 because of the secondaries; now, is u dont have secondaries then you should move vtec to a higher rpm if not ull bog out and LOSE power not gain.I dont think honda set vtec in the b16,b17,b18c6/6 in the 5-6k range if they would be loosing power

 

heres a little test for you to know what is what on the GSR system.

It is called the VVIS system which has the long and short runners.
VTEC kicks in at 4400rpm which is the event at the cam lobes...
secondaries help those lobes out when it switches at 5700rpm.

if you remove the vaccum from the IAB valve, you will have secondaries
all the time. having disassembled the IM so I could port the butterfly ports
inside... if you suck on the vaccum it opens the butterflies. they are normally
shut at zero vaccum. so with that established... then do a 2nd gear pull.
you will see that there is a little POP at 4400 rpm. that is VTEC engaging.
leaving the secondaries open down there makes a bit of a bump in the fuel curve which makes you feel the little VTEC hump it creates. and it makes your takeoff
slower... I never dynoed my car with straight up secondaries though... it would be interesting to see how much low end is lost.

I would like to experiment with that and large cams/full tuning on the dyno.

 

OE P72 = VTEC at 4400, IAB's at 5700 as most others have stated...

 

large cams + raised compression + ported butterfly plate =

 

Dude. I don't know about other cars but my 94 kicks in about 5700 and my 98 about 5000. Don't know. I thought they were all the same.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HIspeedSUSHI &raquo;</TD></TR><TR><TD CLASS="quote">Dude. I don't know about other cars but my 94 kicks in about 5700 and my 98 about 5000. Don't know. I thought they were all the same. </TD></TR></TABLE>
If your VTEC x-over there your ECU wasn't stock... For all P72's (OBD1-2b) it is ~4400/5700rpm

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kataku2K3 &raquo;</TD></TR><TR><TD CLASS="quote">OE P72 = VTEC at 4400, IAB's at 5700 as most others have stated... </TD></TR></TABLE>

I hope people dont associate hearing the engine getting louder as VTEC engaging... u cant hear VTEC engage... most likely people hear the IAB's open up ...

what he said

 

VTEC = is the audible POP at ~4400rpm... IAB's are not so much... It's probably easiest to hear them on a STOCK GSR with an intake... It's just like having a set up ITB's in your plenum, do you hear a sharp change in pitch when you go to WOT with ITB's??? I don't think so Latez

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Civtek &raquo;</TD></TR><TR><TD CLASS="quote">

I hope people dont associate hearing the engine getting louder as VTEC engaging... u cant hear VTEC engage... most likely people hear the IAB's open up ...

what he said </TD></TR></TABLE>

Actually it's the other way around. Vtec crossover is more audible. When the secondaries open up, you don't hear it as much...but you definately feel it more.

-Rod

 

it all depends. completely stock GSR you cant hear either.

I ported mine so that the butterflies are there, but in a set of tapered ports.
once mine open with that R block in there... it almost sounds like ITR VTEC.
at 0,0 cams you cant hear/feel vtec which is good. usually when vtec pops its because there is a lack of power in that spot. speaking generally.